In general, no!
But if we have to replace a lot of lines (accident, resistance too low), it may be more advantageous to change everything.
Before thinking about changing all the lines, you have to make sure that the fabric is still good. There is no point in replacing the lines of a porous paraglider!
The only line subject to constant wear by friction is the main brake line. It passes through a pulley or a low friction ring. This line requires special attention and requires several replacements during the life of the paraglider.
During a full check, we measure the strength of the lines. It happens (quite rarely!) that it is too weak and that the replacement of lines is essential. Most often, we have to replace the lower lines A and B in this way.
Tandem paragliders used intensively require special attention and require several replacements of the lower lines during their lifetime.
